Self-closing vent plug



July 31, 1956 o. G. DUNCAN SELF-CLOSING VENT PLUG 2 Ill/1w! Filed Oct. 11, 1954 8 MP 2 HM l ii i l INVENTOR Owen. Duncan.

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United States Patent' O This invention 'appertainsto a novel vent plug'for -storage batteries and is an improvement over the vent plugs shown in my prior Patents'No.'2,660,611 and No.

2,682,569 issued tome respectively on November 24, 1953, and June 29, 1954.

One ofthe primary objects; of my present invention is to provide a self-closing.vent...plug.which is quick and positive in action, and one which will effectively close automatically..when thebattery -is tilted beyond a certain definite .angle.

Another salientobjectof my invention is to provide means .whereby the-actuating weight or body is provided with a flat face .ofiaminimum resting-area, soas'to eliminate the forming of a positive seat and thus prevent the sticking of the weight and to insure the positive tilting thereof to force a flexible valve carried thereby in sealing contact with the outer wall of the vent plug and over the vent opening therein.

Another important object of my invention is to provide a novel means of associating a flexible valve with the weight, whereby not only case of assembly will be had but whereby the active face of the valve will be at all times accurately positioned relative to the weight.

A further important object of my invention is to provide an exceedingly compact arrangement of self-closing vent plug so that a minimum amount of protrusion will be formed on the battery cover and in which the sealing of the vent opening is brought about by the mere tilting action only of a weight or body.

With these and other objects in view, the invention consists in the novel construction, arrangement and formation of parts, as will be hereinafter more specifically described and claimed and illustrated in the accompanying drawing, in which drawing,

Figure 1 is a fragmentary vertical sectional view through the upper end of a storage battery showing my novel vent plug associated therewith, the plug being shown in vertical section and the battery and the plug being disposed in their normal upright position;

Figure 2 is a view similar to Figure 1, but showing the battery in a partly tilted position and the weight tilted to cause the closing of the vent opening or port;

Figure 3 is a view similar to Figures 1 and 2 but showing the battery completely turned over with the vent sealed;

Figure 4 is an enlarged detail vertical sectional view through the weight or tilting body, illustrating the means employed for associating the flexible valve therewith, and

Figure 5 is a top plan view of the valve and weight the view being on the same scale as Figures 1, 2 and 3.

Referring to the drawing in detail, wherein similar reference characters designate corresponding parts throughout the several views, the letter P generally indicates my improved vent plug for a storage battery B.

The battery B can be considered of a type now commonly found in the open market but preferably of a character for use with airplanes, motorcycles and the like. The battery B will not be described in minute detail, but

rammed July .31, 1956 :the .same includes a case 10 having a top wall 11 provided with a vent. opening 12, the wall of which is threaded. Thecase 10\houses thetcells of .the'battery and contains the acid or electrolyte 13.

My novel ventplug P includes a hollow body 14 having a cylindrical side wall'15, a bottom wall 16 and a top wall 17. This provides an. interior chamber 18. The bottom wall 16 has formed thereon an exteriorly threaded stem. 19 for engagementwith the threads of the opening 12 and communication is bad between the chamber 18 .and the interior of the battery through the stem. The

'coverll. The bottom wall 16 forms an interior shoulder and this shoulder has formed therein radially extending vent grooves'20 for a purpose, which will later appear.

The top wall 17 of the vent plug is formed separate from the side wall 15 for the purpose of assembling the various parts of the vent plug, and after the assembly of such parts the top wall 17 can be securely sealed to the side wall 15. An axially disposed vent port 21 is 'formed in the top wall and generated gases normally escape from the battery through the stem 19 into the chamber 18, and thence into the atmosphere through the vent port 21.

Mounted within-the chamber 18 is a Weight 22 of a desired mass, and preferably, but not necessarily, formed from lead. The weight 22 is of a frusto-conical shape and gradually tapers from its base toward its upper end and this weight is of a considerably less height than the height of the chamber 18. By referring to Figure 4, it can be seen that the weight 22 has. formed in its base portion a circular recess 23 which defines a depending rim 24. The rim 24 normally rests on the bottom wall 16 or the annular shoulder defined thereby, and when the weight is seated on the wall 16 escape of gases and vapor around the weight is permitted by the grooves 20. It is to be also noted at this time, that the largest diameter of the weight is slightly less than the interior diameter of the chamber 18. The weight 22 is also provided with an axially disposed, longitudinal bore 25 which opens out through the upper end of the weight and into the recess 23.

The weight carries a flexible sealing valve 26, which I term of the umbrella type and this valve is preferably formed from soft rubber, neoprene or equivalent material, and has a flat outer face 27. The valve is of an inverted conical shape and has formed on its apex a depending axially disposed flexible and resilient stem 28, which is also formed from rubber. The stem is of a less diameter than the bore 25 and the same has formed thereon cornpressible stop pads or shoulders 29 and 39. The upper shoulder 29 is positioned an exact distance from the apex of the valve 26 so that the valve will be an exact distance from the weight 22 when the valve is associated with the weight. The stem 28 is threaded through the bore and the stop shoulders 29 and 30 engage the walls of the bore at the opposite ends thereof. In actual practice, the stem is provided with an elongated tail (not shown), which is threaded into the bore from the top thereof and when this tail protrudes through the bore the same is forcibly grasped and the stem is pulled into the bore until the lower stop shoulder rides out of the bore and expands to its normal shape. At this time, the tail is severed just below the lower stop shoulder.

In operation of my improved vent plug, upon the tilting of the battery, as shown in Figure 2, the weight will tilt therewith on a part of the outer periphery of its rim 24 and owing to its conical shape, the weight will fall against the side wall 15' of the vent plug and at an angle to the axial center of the plug. This rocking action of the weight moves the flexible valve 26 outwardly into intimate sealing contact with the inner surface of the top wall 17 around the vent port 21, which effectively closes this vent port and the valve 26 is held in its sealing contact by the tilting of the weight. The chamber 18, the weight 22 and the valve 26 are accurately proportioned so that normally the valve 26 is just a slight distance from the inner surface of the top wall 17, as best shown in Figure 1.

As shown in Figure 3, when the battery is completely inverted, the mass of the weight is against the valve and the valve is held tight in its sealing contact around the vent port. Due to the flexibility of the valve and particularly the stem 28, the weight 22 is free to rock with the stem and this will not disturb the seating of the valve.

It is to be noted that there is a minimum amount of area contact between the base of the weight and the bottom wall 16 and hence sticking of the weight is prevented and the weight will positively tilt upon the tilting of the battery. As the valve is entirely closed by a mere tilting action, the sealing of the vent port is quick and positive.

In order to prevent the collection of gases under the weight, the weight itself can be provided with a diagonally extending vent bore 31.

Due to the smooth face 27 of the valve 26, there is a tendency of the valve to stick to the inner face of the outer wall 17 of the hollow body 14, and to prevent this I prefer to roughen the inner face of the wall 17 at a point slightly spaced from the vent port 21.

Changes in details may be made without departing from .4 the spirit or the scope of this invention, but what I claim as new is:

A self-closing vent plug for storage batteries comprising a hollow body having an interior chamber and an opening for communication with the interior of a storage battery and the lower portion of the chamber and an atmospheric vent port communicating with the axial center of the chamber at the upper end thereof, and a frusto-conical weight of a less height than the height of the chamber disposed in said chamber having a recess formed in its lower face defining an annular rim and an axially disposed bore opening into said recess and out of the upper end of the weight, said weight also having a diagonally extending vent bore communicating with the interior of the recess and opening out through the outer side face of the weight, a flexible stem disposed in said bore, stop shoulders on the stem engaging the walls of the bore at the opposite ends thereof, and an upwardly extending flexible valve having a smooth outer face adapted to seal around the vent port upon the tilting of the weight on its rim when the battery is moved beyond a certain angle relative to the vertical.

References Cited in the file of this patent UNITED STATES PATENTS 2,405,736 Dailey et al Aug. 13, 1946 2,480,850 Goldberg Sept. 6, 1950 2,619,102 Endress Nov. 25, 1952 2,660,611 Duncan Nov. 24, 1953 2,682,569 Duncan June 29, 1954 

